The present invention is concerned with a circuit configuration for actuating active- and/or passive-operated warning signal generators which, upon failure of the supply voltage of the electronic system, will generate a warning signal.
Circuit assemblies of the afore-described type are needed, for example, in automotive vehicles furnished with electronic control systems. Control systems of this type include anti-locking control systems, traction slip control systems, driving stability control systems etc. Upon occurrence of an error, such as failure of the supply voltage of the electronic system, an alarm lamp is actuated or a different warning signal released. As malfunctions of this type are likely to involve danger, the circuit arrangements should be so configured as to insure flashing of a warning lamp also in case of a defective condition of the monitoring system itself or of the actuation system of the warning lamp.
DE 43 10 530 A1 already teaches a circuit configuration for actuating a warning lamp, comprising a self-conductive transistor circuit which, in the event of a failure of supply voltage in the electronic system insures a power flow to chassis from the supply source of the warning lamp across the said warning lamp and across the self-conductive transistor circuit. However, flashing of the warning lamp in the event of such a failure requires a "passive" operation of the warning lamp, i.e. a conduction of the warning lamp flow across the actuating connection and across the final phase of the warning lamp actuation. However, also "active"-operated warning lamps are known in the art that will flash even in the absence of an actuating signal. Consequently, the output of the warning signal actuating phase must become high-resistive in the event of a failure of the actuating electronic system; a self-conducting transistor circuit would, in that case, prevent the (active-operated) warning lamp from flashing.
It is, therefore, the object of the present invention to provide a circuit configuration for actuating warning lamps and other alarm signal generators to which can be connected both active and passive (i.e. active- and passive-operated) warning signal generators, nevertheless insuring, upon failure of the electronic system, in particular, of the supply voltage, flashing of the warning lamp will or releasing of a warning signal.